An alcohol is an organic substance having a chemical formula of CnH2n+1OH. While not the dominant energy resource used throughout the world today, alcohols have been used as fuels throughout the course of history. The first four aliphatic alcohols include methanol, ethanol, propanol, and butanol. These alcohols, as well as others, can be used as fuels in current engines and systems. Fuel alcohols can be advantageous because they can be synthesized chemically or biologically, in some instances provide greater fuel economy than most fossil fuels (e.g., gasoline, diesel), and typically produce less harmful byproducts when burned.
Like reference symbols and designations in the various drawings indicate like elements.